This study is a first-in-human (Phase 1) study using three dose levels of an investigational vaccine directed against Staphylococcus aureus (SA3Ag). This study is primarily designed to assess how safe and well tolerated SA3Ag is, but will also describe the immune response over 12 months elicited by SA3Ag. Additionally, this study will assess the effect of SA3Ag vaccine on the number of Staphylococcus aureus bacteria that naturally occur on the skin and within the nose and throat.